Development and quality of cloudberry (Rubus chamaemorus L.) as affected by female parent, male parent and temperature

Abstract

In this study we investigated the interaction between temperature and genotype on fruit development and levels of total phenols and anthocyanins in cloudberry. The experiment was done in a phytotron using one female (‘Fjellgull') and one hermaphroditic (‘Nyby') cultivar. Plants were grown at 9, 12, 15 and 18°C in 24-h photoperiod. The female cultivars were pollinated with pollen from a male (‘Apollen') clone and from the hermaphrodite clone. Parthenocarpic fruit development was induced by gibberellic acid (GA₃). Ripe berries were frozen individually at −80°C and stored until analyses. There was a linear, double logarithmic relationship between temperature and number of days from pollination/GA₃-treatment to ripening. ‘Fjellgull' had significantly larger berries than ‘Nyby', and the largest berries were obtained at 12 and 9°C. Pollen clone did not have a significant effect on berry size. GA₃ induced parthenogenesis in ‘Fjellgull' and partial parthenogenesis in ‘Nyby'. In ‘Fjellgull', the parthenocarpic berries were comparable to pollinated ones at low temperatures, but at 18°C their development was restricted. The level of total anthocyanins was significantly higher in ‘Fjellgull' than in ‘Nyby', and these levels were significantly enhanced at 9 and 12°C compared to higher temperatures. Levels of total phenolic compounds were not significantly affected. In conclusion, the present results indicate that low temperature is favourable both for size and quality of cloudberries.